The number 6 has a special significance. It represents the Law and Order and also associated with a Karmic Law of cause and effect. Number 6 is a perfect number, symmetrical in all parts, the number of the Soul.
Plums are ready they are not hard as a rock, soft just a little when pressed. I wouldn't use windfall, they are too ripe. If your making jam, it is best to use some underripe with the ripe ones. Last season I added small diced candied ginger to the plum jam. Really turned out nice.
Storing Plums Before Ripening. Unripe plums store best at temperatures between 31 and 32 F and at 90 to 95 percent humidity. Commercial growers are able to store plums for two to four weeks under these conditions before ripening. Unripe plums stored in temperatures above 66 F can develop Rhizopus Rot.